(a) Field of the Invention
The present invention is related to a light guide plate locating construction, and more particularly, to one that is applied in a backlight unit to locate the light guide plate in position so to protect light tubes from being hit by the light guide plate.
(b) Description of the Prior Art
LED applied in an information system may be adapted with a direct or side type of backlight unit configuration depending on the design requirements. FIG. 1 of the accompanying drawings shows a schematic view of a basic construction of a side type backlight unit configuration. Wherein, a backlight unit 1 includes a light guide plate 11, a tube 12 and a mask 13. The mask 13 is made of hard metal material and the tube 12 is clad in the mask 13 to facilitate the mounting of the mask on one end side of the light guide plate 11 to take advantage of the mask 13 as an aid to reflect streams of light, thus to guide massive streams of light emitted from the tube 12 into the light guide plate 11. Streams of light passing through the light guide 1 are upwardly directed to leave the backlight unit 1.
The sideway section of the mask 13 is made in a shape of  to define a top 131, a side 132, and a bottom 133. To prevent the edge of the light guide plate 11 from sliding into the mask 13 to hit and break the tube 12, a  shaped opening is cut from bottom 133 of the mask 13 so to define on the bottom 133 a flat part having its one side connected and the other three sides cut through. The flat part is raised by its three sides to define a retaining part 15 and the longer the cut is, the larger the  shaped opening gets. However, the construction for the retaining part 15 is found with the following flaws:
1. The height of the retaining part 15 is limited for facilitating the installation of the tube 12 and the light guide plate 11, also for avoiding excessively greater opening of the mask to affect its effect of reflecting the light; meanwhile, the effect of preventing the light guide plate 11 from hitting the tube 12 is compromised.
2. The retaining part 15 is formed by cutting and pushing up a portion of the bottom 133 of the mask and is connected to only one side of the bottom 133 is vulnerable to deformation thus to fail its purpose of preventing the light guide plate 11 form hitting the tube 12 due to that the retaining part is always subject to side push by the light guide plate 15 and gets fatigue and that it can get easily bent by the push force from the light guide plate.